1. Field of the Invention
The present invention relates to blends of a polycarbonate resin and an interpolymer modifier, said blends having good processing characteristics, impact resistance and weatherability. The resulting blends are useful in the production of weatherable, impact resistant molded and shaped articles.
2. Description of the Prior Art
Polycarbonate resins are tough, rigid engineering thermoplastics having good impact strength. They, however, have low flow characteristics which sometimes causes difficulties in processing. Various prior art attempts have been made to blend polycarbonate resins with other polymeric modifiers to solve this problem while still retaining the toughness and impact resistance of the polycarbonate resin.
Acrylonitrile-butadiene-styrene (ABS) graft copolymers have been blended with polycarbonate resins to yield a lower cost blend having improved processing characteristics while retaining good impact resistance (see U.S. Pat. No. 3,130,177 to T. S. Grabowski, and Plastics World, November 1977, pp. 56-58). The impact resistance of such blends, however, tends to deteriorate after the material has been exposed to such environmental factors as sunlight.
Blends of polycarbonate resin and acrylic/styrene polymers are also known (U.S. Pat. No. 3,655,826 to R. P. Fellmann et al. and Japanese Patent Document No. 52-94349).